1. Field of the Invention
This invention relates to electric motor systems, and is more particularly concerned with increasing the efficiency of electric motors, particularly d.c. motors, so that energy consumption occurs only during periods of driving and energy is returned to the power source during intervals between periods of driving.
2. Description of the Prior Art
As set forth in my United States Letters Patent No. 3,611,091, granted Oct. 5, 1971, the utilization of battery charging apparatus in conjunction with the operation of a direct current motor is well known in the art. It was pointed out in that patent that battery charging, via capacitors and the like, have heretofore been relatively inefficient from a total system standpoint in that battery charging is only incidental, and not of major concern, to the overall operation of the system.
In my aforementioned patent, I provided a plurality of sources and commutation apparatus for interchanging connections during operation whereby a single source at a time was utilized during a driving interval, while another source or sources were receiving a charging current which was created during the field collapse during non-driving intervals in an amount of from one-third to one-half of the current consumed.